Comparing electric fields with gravitational fields
Section: Electric Fields | Syllabus: Cambridge AS Level Physics 9702
Similarities and Differences Both electric and gravitational fields describe how objects with certain properties (charge or mass) interact across space without contact. Feature Gravitational Fields Electric Fields Source Mass (m) Charge (Q) Force Law Inverse Square (F 1/r^2) Inverse Square (F 1/r^2) Type of Force Always Attractive Attractive or Repulsive Field Strength g = GM/r^2 (Radial) E = Q/4πε_0 r^2 (Radial) Potential Always Negative (V = -GM/r) Positive or Negative (V = Q/4πε_0 r) Work Done W = mΔ V W = qΔ V Key Takeaway The pattern of field lines for a point mass is identical to that of a point negative charge (both radial and directed inwards).
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